The present invention relates to electronic packaging, and more particularly relates to circuitized substrates which may be used to carry semiconductor chips, or other such electronic devices.
Typically, semiconductor chips are mounted on circuitized substrates, known as semiconductor chip carriers, having electrical circuit lines for connecting the chip to a printed circuit board, or other such structure, which may be used as part of a computer, or other such equipment. There are many important considerations in selecting a suitable semiconductor chip carrier for a particular application. For example, an important consideration may be the ability of the semiconductor chip carrier to relieve thermal strains during manufacture and use of equipment incorporating a semiconductor chip, the semiconductor chip carrier, and a printed circuit board, each having a different coefficient of thermal expansion. Another consideration may be the ability to manufacture the semiconductor chip carrier in a form suitable for use in a relatively high volume, manufacturing environment. A further consideration may be the ability of the semiconductor chip carrier to support relatively fine circuit lines. A still further consideration may be the ability to mount a semiconductor chip on the semiconductor chip carrier using an area or peripiheral array attachment configuration. The foregoing are examples of just some of the considerations that may be important for selecting a semiconductor chip carrier for use in a particular application.
Of course, there are a number of known semiconductor chip carriers, and other such circuitized substrates, designed for use in particular applications. Such substrates include metallized ceramic, and circuitized, flexible film substrates as described in U.S. Pat. Nos. 4,517,051, 4,480,288, and 4,231,154. However, there are many other applications requiring circuitized substrates having other features and advantages. For example, there is a need to provide circuitized substrates having relatively fine circuit lines to which semiconductor chip may be connected in an array or peripheral area configuration. In addition, there is an especially important need for circuitized, flexible film substrates which may be manufactured in a form suitable for use in a relatively high volume, manufacturing environment, and/or in a form suitable for use with automated manufacturing equipment.